imobiliser problem,vw t4 caravelle.

Hi, I have had an intermitant fault,my 2.5 tdi 102 bhp,w reg t4 caravelle wouldn't start.normally it fires up with the first turn of the key.but sometimes it will turnover ok but not start,then after a few hours or less it will start again,this has started happening more and more frequently.I have checked glowplugs,relays,fuses,fuel all seem ok.So it seems like it must be the imobiliser thats fualty,on the t4 there is a black ring round the ignition barrel with a wire to it which reads the signal from the chip in the key.I think there is a fault with it but what the fault is and how to repair it i don't know, does anybody have any ideas or experience of this.
frustrated green machine surf bus owner mohammad.:mad:

the ring around the ignition barrel reads the chip in the key and then sends a singal to the immobilizer module, which then either accepts or rejects the code, and thus either permits the van to start. I have had the same problem on a honda before and the only fix was to buy a new code reader, and the immobilzer, along with new programmed keys.

speak to you main dealer and see what they quote you.

hth

Hi Siddiq

I am not able to help you, but will like to discus it with you.

Actually I think I have se same problem with my T4 as you have

My T4 is also a 2.5 TDI – it is from year 2000.

It has also always stated immediately, but within the last months, I first a couple of times observed that when I tried to start the engine it was just firing for a few turnings and then got out - just like it was able to run with that diesel which was in the pump but no new fuel got to the pump. Next time (after half a second) I tried to start no problem occurs.

One time it was not able to start - engine just turning but no ignition. After a few attempts it’s started ok.

For two weeks ago it wasn’t able to start at all. I tried a lot of time (more than 10 times in 3 hours). Then I changed the button switch in the ignition barrel, and after that it was starting OK.


BUT – yesterday it wasn’t able to start at all, tried a lot of time over some hours.

And now I have left it, and hope a friend of some of my friends will come with a diagnostic program so that we can read out errors codes.

But why do You thing it is a immobiliser problem? Why not just a problem with a valve or with a input signal???

Regards Ole

have you changed realy 109, that was the problem with mine

Mohammed,

I had a problem with my 2001 2.5tdi Caravelle - car ran fine, parked up overnight, next day wouldn't start. I tried all sorts (with the help of this and other similar forums) without success - van would simply churn over and make no attempt to start. I thought immobiliser too but before I got into how to test or even replace it, I came across some advice about a problem with the wiring lom in the engine bay above the gearbox. In my case, I had a broken switched earth return. I've 'fixed' it temporarily by earthing from the relevant relay. I'll try and dig out the post and send it on.

Dan

Mohammed,

This is the post
https://www.vwaudiforum.co.uk/forum/s...ight=tdi+start

Dan